1. Field of the Invention
The present invention relates to a motor driver including electronic components for driving or controlling a motor, and a cabinet including such electronic components.
2. Description of the Related Art
Some motor drivers mounted inside cabinets are equipped with a fan motor. When the fan motor is in operation, air passes through the inside of the motor driver, thereby cooling the motor driver. However, when the fan motor is in operation, mist of cutting fluid scattered from the machine tool is accumulated at the fan motor, and the cutting fluid consequently adheres to the fan motor, in some cases. The cutting fluid adhering to the fan motor drops, in the form of water drops or oil drops, down to the electronic components positioned below the fan motor in the motor driver, which may cause a breakdown of the electronic components.
To address this problem, in Japanese Patent Application Laid-Open Publication No. H09-172281, a fan motor is attached so as to be inclined with respect to a horizontal plane. Further, in Japanese Patent Application Laid-Open Publication No. 2007-48946, a plane for mounting a fan motor is inclined. Accordingly, in Japanese Patent Application Laid-Open Publication No. H09-172281 and Japanese Patent Application Laid-Open Publication No. 2007-48946, cutting fluid is guided to a certain area where no electronic components are disposed.
In some cases, a laterally-extending wall is disposed above a motor driver. In such a case, mist of cutting fluid sprayed from the motor driver onto the wall by a fan motor is accumulated on the wall and thereby forms a fluid pool. When a certain amount of cutting fluid is accumulated, the cutting fluid drops from the wall down to the motor driver under its own weight. Then, the cutting fluid flows into the motor driver through a gap at a top plate of the motor driver, which may cause a breakdown of the electronic components.
Although fan motors are normally attached to the upper end of a motor driver, some fan motors are attached to an inner part of a motor driver with a distance from the upper end of the motor driver. In such a case, mist of cutting fluid is sprayed onto an inner surface of a top plate of the housing of the motor driver by a fan motor, and accumulated at the inner surface. Then, the cutting fluid thus accumulated drops from the inner surface of the top plate down to the electronic components in the motor driver, which may cause a breakdown of the electronic components as in the above case.
The present invention has been made in view of the above circumstances, and aims to provide a motor driver and a cabinet that are capable of preventing a breakdown of electronic components mounted therein, due to cutting fluid.